Members Subjected to Torsion Combined with Other Actions

The combination of torsion with bending and shear (T-M-V) in members with both transverse and longitudinal reinforcement is the most commonly encountered combination in practical cases. Three dimensional interaction surfaces have been suggested by Hsu in 1968, Johnston in 1971, McGee in 1974 Elfren et al. in 1974. These surfaces were basically based on the interaction curves between each two stress-resultants at a time. Due to the limitations associated with experimental testing to cover all the possible factors that influence the interaction surface, theoretical models can be effectively used to establish this interaction. Currently available models such as that developed by Ewida and McMullen in 1981 have the ability to calculate the full response members subjected to the T-V-M combinations. Other more advanced models such as those developed by Rabbat and Collins in 1978 and by Rahal and Collins in 1995 are capable calculating the full response of reinforced and prestressed concrete beams subjected to any possible combination of stress-resultants.